diff --git a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersOnAddReviewer.java b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersOnAddReviewer.java
index a7c2f27..9352e97 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersOnAddReviewer.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersOnAddReviewer.java
@@ -25,8 +25,10 @@
 import com.google.gerrit.extensions.common.AccountInfo;
 import com.google.gerrit.extensions.events.ReviewerAddedListener;
 import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.metrics.Timer0;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfigSnapshot;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfiguration;
+import com.google.gerrit.plugins.codeowners.metrics.CodeOwnerMetrics;
 import com.google.gerrit.plugins.codeowners.util.JgitPath;
 import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.CurrentUser;
@@ -65,6 +67,7 @@
   private final ChangeNotes.Factory changeNotesFactory;
   private final AccountCache accountCache;
   private final ChangeMessagesUtil changeMessageUtil;
+  private final CodeOwnerMetrics codeOwnerMetrics;
 
   @Inject
   CodeOwnersOnAddReviewer(
@@ -74,7 +77,8 @@
       RetryHelper retryHelper,
       ChangeNotes.Factory changeNotesFactory,
       AccountCache accountCache,
-      ChangeMessagesUtil changeMessageUtil) {
+      ChangeMessagesUtil changeMessageUtil,
+      CodeOwnerMetrics codeOwnerMetrics) {
     this.codeOwnersPluginConfiguration = codeOwnersPluginConfiguration;
     this.codeOwnerApprovalCheck = codeOwnerApprovalCheck;
     this.userProvider = userProvider;
@@ -82,6 +86,7 @@
     this.changeNotesFactory = changeNotesFactory;
     this.accountCache = accountCache;
     this.changeMessageUtil = changeMessageUtil;
+    this.codeOwnerMetrics = codeOwnerMetrics;
   }
 
   @Override
@@ -96,7 +101,7 @@
       return;
     }
 
-    try {
+    try (Timer0.Context ctx = codeOwnerMetrics.addChangeMessageOnAddReviewer.start()) {
       retryHelper
           .changeUpdate(
               "addCodeOwnersMessageOnAddReviewer",
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
index 7f2cd2b..101cedd 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
@@ -20,9 +20,11 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.metrics.Timer0;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfigSnapshot;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfiguration;
 import com.google.gerrit.plugins.codeowners.backend.config.RequiredApproval;
+import com.google.gerrit.plugins.codeowners.metrics.CodeOwnerMetrics;
 import com.google.gerrit.plugins.codeowners.util.JgitPath;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.notedb.ChangeNotes;
@@ -54,13 +56,16 @@
 
   private final CodeOwnersPluginConfiguration codeOwnersPluginConfiguration;
   private final CodeOwnerApprovalCheck codeOwnerApprovalCheck;
+  private final CodeOwnerMetrics codeOwnerMetrics;
 
   @Inject
   OnCodeOwnerApproval(
       CodeOwnersPluginConfiguration codeOwnersPluginConfiguration,
-      CodeOwnerApprovalCheck codeOwnerApprovalCheck) {
+      CodeOwnerApprovalCheck codeOwnerApprovalCheck,
+      CodeOwnerMetrics codeOwnerMetrics) {
     this.codeOwnersPluginConfiguration = codeOwnersPluginConfiguration;
     this.codeOwnerApprovalCheck = codeOwnerApprovalCheck;
+    this.codeOwnerMetrics = codeOwnerMetrics;
   }
 
   @Override
@@ -90,8 +95,10 @@
       return Optional.empty();
     }
 
-    return buildMessageForCodeOwnerApproval(
-        user, changeNotes, patchSet, oldApprovals, approvals, requiredApproval);
+    try (Timer0.Context ctx = codeOwnerMetrics.extendChangeMessageOnPostReview.start()) {
+      return buildMessageForCodeOwnerApproval(
+          user, changeNotes, patchSet, oldApprovals, approvals, requiredApproval);
+    }
   }
 
   private Optional<String> buildMessageForCodeOwnerApproval(
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerOverride.java b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerOverride.java
index c06e760..db3f936 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerOverride.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerOverride.java
@@ -21,9 +21,11 @@
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.entities.PatchSet;
+import com.google.gerrit.metrics.Timer0;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfigSnapshot;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfiguration;
 import com.google.gerrit.plugins.codeowners.backend.config.RequiredApproval;
+import com.google.gerrit.plugins.codeowners.metrics.CodeOwnerMetrics;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.restapi.change.OnPostReview;
@@ -45,10 +47,14 @@
 @Singleton
 class OnCodeOwnerOverride implements OnPostReview {
   private final CodeOwnersPluginConfiguration codeOwnersPluginConfiguration;
+  private final CodeOwnerMetrics codeOwnerMetrics;
 
   @Inject
-  OnCodeOwnerOverride(CodeOwnersPluginConfiguration codeOwnersPluginConfiguration) {
+  OnCodeOwnerOverride(
+      CodeOwnersPluginConfiguration codeOwnersPluginConfiguration,
+      CodeOwnerMetrics codeOwnerMetrics) {
     this.codeOwnersPluginConfiguration = codeOwnersPluginConfiguration;
+    this.codeOwnerMetrics = codeOwnerMetrics;
   }
 
   @Override
@@ -69,27 +75,32 @@
       return Optional.empty();
     }
 
-    ImmutableList<RequiredApproval> overrideApprovals =
+    ImmutableList<RequiredApproval> appliedOverrideApprovals =
         codeOwnersConfig.getOverrideApproval().stream()
             .sorted(comparing(RequiredApproval::toString))
+            // If oldApprovals doesn't contain the label or if the labels value in it is null, the
+            // label was not changed.
+            .filter(
+                overrideApproval ->
+                    oldApprovals.get(overrideApproval.labelType().getName()) != null)
             .collect(toImmutableList());
 
-    List<String> messages = new ArrayList<>();
-    for (RequiredApproval overrideApproval : overrideApprovals) {
-      if (oldApprovals.get(overrideApproval.labelType().getName()) == null) {
-        // If oldApprovals doesn't contain the label or if the labels value in it is null, the label
-        // was not changed.
-        continue;
-      }
-
-      buildMessageForCodeOwnerOverride(user, patchSet, oldApprovals, approvals, overrideApproval)
-          .ifPresent(messages::add);
-    }
-
-    if (messages.isEmpty()) {
+    if (appliedOverrideApprovals.isEmpty()) {
       return Optional.empty();
     }
-    return Optional.of(Joiner.on("\n\n").join(messages));
+
+    try (Timer0.Context ctx = codeOwnerMetrics.extendChangeMessageOnPostReview.start()) {
+      List<String> messages = new ArrayList<>();
+      appliedOverrideApprovals.forEach(
+          overrideApproval ->
+              buildMessageForCodeOwnerOverride(
+                      user, patchSet, oldApprovals, approvals, overrideApproval)
+                  .ifPresent(messages::add));
+      if (messages.isEmpty()) {
+        return Optional.empty();
+      }
+      return Optional.of(Joiner.on("\n\n").join(messages));
+    }
   }
 
   private Optional<String> buildMessageForCodeOwnerOverride(
diff --git a/java/com/google/gerrit/plugins/codeowners/metrics/CodeOwnerMetrics.java b/java/com/google/gerrit/plugins/codeowners/metrics/CodeOwnerMetrics.java
index 5d523a6..22de56d 100644
--- a/java/com/google/gerrit/plugins/codeowners/metrics/CodeOwnerMetrics.java
+++ b/java/com/google/gerrit/plugins/codeowners/metrics/CodeOwnerMetrics.java
@@ -29,11 +29,13 @@
 @Singleton
 public class CodeOwnerMetrics {
   // latency metrics
+  public final Timer0 addChangeMessageOnAddReviewer;
   public final Timer0 computeChangedFilesAgainstAutoMerge;
   public final Timer0 computeChangedFilesAgainstFirstParent;
   public final Timer0 computeFileStatus;
   public final Timer0 computeFileStatuses;
   public final Timer0 computeOwnedPaths;
+  public final Timer0 extendChangeMessageOnPostReview;
   public final Timer0 prepareFileStatusComputation;
   public final Timer0 prepareFileStatusComputationForAccount;
   public final Timer0 resolveCodeOwnerConfig;
@@ -61,6 +63,11 @@
     this.metricMaker = metricMaker;
 
     // latency metrics
+    this.addChangeMessageOnAddReviewer =
+        createLatencyTimer(
+            "add_change_message_on_add_reviewer",
+            "Latency for adding a change message with the owned path when a code owner is added as"
+                + " a reviewer");
     this.computeChangedFilesAgainstAutoMerge =
         createLatencyTimer(
             "compute_changed_files_against_auto_merge",
@@ -80,6 +87,11 @@
         createLatencyTimer(
             "compute_owned_paths",
             "Latency for computing the files in a change that are owned by a user");
+    this.extendChangeMessageOnPostReview =
+        createLatencyTimer(
+            "extend_change_message_on_post_review",
+            "Latency for extending the change message with the owned path when a code owner"
+                + " approval is applied");
     this.prepareFileStatusComputation =
         createLatencyTimer(
             "prepare_file_status_computation", "Latency for preparing the file status computation");
diff --git a/resources/Documentation/metrics.md b/resources/Documentation/metrics.md
index 8e6ee6d..b4512f2 100644
--- a/resources/Documentation/metrics.md
+++ b/resources/Documentation/metrics.md
@@ -5,6 +5,9 @@
 
 ## <a id="latencyMetrics"> Latency Metrics
 
+* `add_change_message_on_add_reviewer`:
+  Latency for adding a change message with the owned path when a code owner is
+  added as a reviewer.
 * `compute_changed_files_against_auto_merge`:
   Latency for computing changed files against auto merge.
 * `compute_changed_files_against_first_parent`:
@@ -17,6 +20,9 @@
   Latency for computing file statuses.
 * `compute_owned_paths`:
   Latency for computing the files in a change that are owned by a user.
+* `extend_change_message_on_post_review`:
+  Latency for extending the change message with the owned path when a code owner
+  approval is applied.
 * `prepare_file_status_computation`:
   Latency for preparing the file status computation.
 * `prepare_file_status_computation_for_account`: